Unilateral lesions of the pedunculopontine nucleus do not alleviate subthalamic nucleus-mediated anticipatory responding in a delayed sensorimotor task in the rat.

Lesions of the subthalamic nucleus (STN) in the rat are known to cause anticipated movements in behavioral tasks requiring a preparatory period before the execution of externally cued conditioned movements. In the present study, we describe the effects of lesions of the pedunculopontine nucleus (PPN), a structure located on the outflow of the STN to lower brainstem and spinal motor nuclei, on the anticipatory responding caused by a unilateral lesion of the STN in a delayed sensorimotor task. Rats were instructed to keep a lever pressed down by the presentation of a composite visual and acoustic signal, and were required to hold the lever pressed until a trigger stimulus occurred after an unpredictable delay. The trigger stimulus required the animals to release the lever and to press a second lever for food reinforcement. The task was evaluated according to analysis of movement parameters and errors made by the animals during the preparative and executive phases of the conditioned movement. An ibotenate lesion was placed into the STN in either side of the brain. This lesion was followed 3 weeks later by an ibotenate lesion of the PPN ipsilaterally to the STN previously lesioned. The results indicate that the anticipatory responding induced by the STN lesion was not alleviated by the subsequent PPN lesion. However, the animals bearing the combined lesion were severely impaired in conditioned responding to salient stimuli involved in the paradigm and showed side-specific lengthening of reaction and movement times without global motor impairments. The results suggest that the anticipatory responses caused by STN lesions do not require the intervention of the PPN and that the disruption of the dopaminergic nigrostriatal pathway following the combined lesion may be responsible for impairments observed.

The function of the pedunculopontine nucleus in the preparation and execution of an externally-cued bar pressing task in the rat.

In the present study the role of the pedunculopontine nucleus (PPN) in the preparation and execution of an externally-cued rewarded motor act was investigated. Animals were instructed to press down a lever at the presentation of a combined visual and acoustic signal and were required to hold down the lever until a trigger stimulus occurred after an unpredictable delay ranging from 2 to 4 s. The trigger stimulus required animals to release the lever and to press a second lever for food reinforcement. The time between instruction and trigger signals represented the preparation phase preceding movement. Unilateral ibotenic acid-induced focal degeneration of pedunculopontine neurons did not influence either reaction and movement times, or capacity of the animals to correctly respond to presentation of stimuli of behavioral significance. On the contrary, bilateral lesions increased both reaction and movement times, and dramatically reduced the percentage of correct responses. The analysis of incorrect responses suggested that the most striking deficit exhibited by the animals following the bilateral lesion was a lack of conditioned response to the signal initiating each trial. However, the animals retained the capability to respond correctly in some trials, and were able to collect the reward when delivered outside the behavioral context. Histological analysis of lesions showed that in addition to loss of neurons within the pedunculopontine region, reduction of tyrosine-hydroxylase positive neurons had occurred in the pars compacta of the substantia nigra. The data suggest that the PPN is involved in the preparation and execution of externally-cued movements, and demonstrate that its destruction mimics the main effects produced by the dopaminergic denervation of the dorsal striatum.

Vitamin E nutritional status and serum lipid pattern in normal weanling rabbits.

In a 6-wk postweaning trial (Trial 1), 30 male New Zealand White rabbits were fed a starter diet with three different levels of all-rac-alpha-tocopheryl acetate (60, 160, or 260 mg/kg diet). Plasma concentrations of alpha-tocopherol and serum concentrations of total cholesterol, high density lipoprotein (HDL) cholesterol, and triglycerides were measured at 2, 4, and 6 wk. In a 20-wk postweaning trial (Trial 2), 48 male New Zealand White rabbits were divided into two groups; one group was fed a vitamin E-free diet, and the other was fed the same diet supplemented with 60 mg/kg of all-rac-alpha-tocopheryl acetate. Plasma concentrations of alpha-tocopherol and serum total cholesterol, HDL cholesterol, and triglycerides were measured at 2, 4, 6, and 20 wk. In Trial 1, split-plot ANOVA showed that dietary all-rac-alpha-tocopheryl acetate increased plasma alpha-tocopherol (P < .01); in addition, serum total cholesterol and triglycerides declined more rapidly (P < .01) and HDL cholesterol increased more rapidly (P < .005) in rabbits fed supplemental all-rac-alpha-tocopheryl acetate than in controls. The all-rac-alpha-tocopheryl acetate intake was significantly correlated with serum total cholesterol reduction and HDL cholesterol increase only when plasma alpha-tocopherol was relatively low (< 23.5 mumol/ L). In trial 2, the vitamin E-free diet caused an increase (P < .05) in total serum cholesterol and a reduction in HDL cholesterol (P < .05 at 6 wk and P < .01 at 20 wk). The overall results of this study suggest that vitamin E plays an important role in the regulation of serum concentrations of cholesterol and lipoproteins in weanling rabbits. Consequently, the maintenance of an adequate nutritional status of vitamin E in the postweaning period is important to avoid alterations of serum lipid pattern.

Tracheobronchial stenosis: role of virtual endoscopy in diagnosis and follow-up after therapy.

PURPOSE: This study was done to evaluate whether virtual endoscopy can be employed as a preliminary technique to shorten the time required for the subsequent endoscopic procedure and be proposed for treatment planning and, postoperatively, for evaluating response to treatment in patients with cancer or severe stenotic lesions. MATERIALS AND METHODS: From December 2004 to October 2005, 25 patients with suspected obstructive tracheobronchial stenosis were studied by contrast-enhanced computed tomography (CT) with multiplanar reconstruction (MPR) and virtual bronchoscopic navigation, after a preliminary clinical and conventional radiology assessment. RESULTS: Quality of the virtual endoscopy images was excellent in all cases. Out of the 25 patients, four were affected by benign lesions and 21 by malignant lesions. With regard to lesion site, virtual endoscopy proved to be as informative as real endoscopy. The virtual endoscope was able to cross severe stenoses with a residual lumen of 3 mm. Follow-up studies were performed in 15 patients treated with laser and cryotherapy. In all cases, evaluation of the degree of post-treatment stenosis was similar to that obtained with conventional endoscopy. CONCLUSIONS: Our study indicates that virtual bronchoscopy has a high diagnostic potential. The technique, with the integration of MPR images, can be proposed as a preliminary study to obtain accurate characterisation of stenoses, to shorten the time required for the subsequent endoscopic procedure and to plan the most appropriate treatment.

Some blood parameters of water buffalo in different physiological conditions.

The Authors have studied the changes of GOT, GPT, ALP, CPK and Se in buffaloes under different physiological conditions (age, diet, different pre and post partum times). 99 adult buffaloes were classified in 8 groups on the basis of different pre, post partum time intervals. Moreover, other 39 animals were divided into 4 groups: A = 60-90 day old animals, fed with reconstituted milk supplemented with Vit E; B = same age, fed with maternal milk; C = 6-8 month old animals; D = 12-18 month old animals. In the various classes of animals blood ALP, GPT, GOT, CPK and Se were monitored. Results showed that the high variability in blood activity of the studied enzymes suggest that in establishing their reference values the physiological condition of the subject and the time interval from the parturition must be taken into account. The fact that Se was not detectable in many pregnant animals suggests that the prevention of myodistrophy in buffalo calves must be effected in prenatal epoch.

Digital sampling rate and ECG analysis.

The influence of sampling rate on the accuracy of measurements of various ECG parameters has been studied. Statistical analysis showed no significant difference between results obtained at sampling rates of 500 and 250 samples s-1. Recordings made at 125 samples s-1, however, showed significant reductions in peak amplitude values. Some interval measurements also varied significantly to both larger and smaller values. Other intervals did not seem to be affected significantly. It is concluded that a sampling rate of 125 samples s-1 could be used in particular conditions when only the measurement of certain intervals is required.

Ethyl alcohol induced skin temperature changes evaluated by thermography. Preliminary results.

The authors have investigated the validity of thermography in the study of ethyl alcohol induced hand blood flow changes in normal subjects before and after a standard meal. The superficial temperature changes of the hand of ten healthy subjects, 7 males and 3 females, 25-40 years old, were recorded in 4 conditions: a) on an empty stomach, b) after ingestion of a standard dose of ethyl alcohol (25 cc of whisky at 40%, corresponding to 10 g of alcohol), c) after a standard meal (1200 Kcal), d) after a standard meal and a standard dose of alcohol. Three male subjects were not drinkers. Arterial blood pressure and ECG were monitored during the different phases of the experiment. Results show a typical time course of the hand temperature in response to intake of alcohol, stronger in fasting non drinkers subjects. Our results confirm the valuable role of thermography in the study of alcohol-induced calorigenic effects.

Hippocampal synaptic plasticity: effects of neonatal stress in freely moving adult male rats.

The present study examines the effects of neonatal isolation on hippocampal LTP in adult male rats. Changes in dentate granule cell population measures, i.e., EPSP slope and population spike amplitude (PSA), evoked by tetanization of the medial perforant pathway were used to assess the effects of neonatal isolation on LTP over a period of 96 h. Following tetanization significant group differences were obtained for input/output (I/O) response measures of EPSP slope and PSA, with isolated males showing consistently higher values than in the other two groups. Comparisons made at 1 h post-tetanization (establishment of LTP) indicated that isolated males showed significantly greater enhancement than any other group. At 96 h (maintenance of LTP), however, neonatally isolated males showed significantly greater enhancement than either non-isolated siblings or unhandled controls. Additionally, isolation resulted in prolonging the duration of enhancement obtained from males. Thus, males show different enhancement profiles with respect to both the magnitude and duration of LTP and neonatal isolation alters these profiles in profound manner.

Simultaneous evaluation of vitamins A and E in human plasma by normal phase HPLC.

The production of toxic oxidants such as H2O2; OH. and O2.- which follows aerobic metabolism is highly enhanced in aging, alcohol consumption and in a variety of degenerative diseases including neoplasias. Among the different antioxidant agents that in human organisms counterbalance the oxidative stress, which damages lipid, protein and DNA, are included beta-carotene, alpha-tocopherol, glutathione, ascorbate, ubiquinol and specific enzymes such as superoxide dismutase, catalase and glutathione peroxidase. In particular, vitamins A and E are the most important lipid-soluble antioxidants in human tissues protecting polyunsaturated fatty acid from peroxidation. In this paper we report an improved method, obtained after modification of a normal phase HPLC method, which allows the simple and rapid simultaneous evaluation of vitamins A and E in plasma. The separation of vitamins is achieved by eluting the HPLC column with a linear gradient from 1 to 5% isopropanol in n-hexane. The eluate is simultaneously monitored by U.V. and fluorescence detection to identify and quantify vitamins A and E, respectively.

Finger tremor and the central nervous system.

It is well known that normal physiological tremor of the fingers and alpha rhythm in the EEG, may share a common frequency band in the region of 10 Hz; that these two characteristics may be in some way related as a function of their frequencies, is a hypothesis which needs to be tested, as one element in establishing the physiology of physiological tremor. Bilateral occipital EEGs and simultaneous measurements of acceleration from the terminal phalanx of the middle finger of both hands were recorded from eight subjects. The data were analysed to produce power spectral densities and coherence functions, the latter being used to reveal the presence or absence of frequency elements common to both signals. No evidence was found that would support a hypothesis that the two characteristics were in any way frequency related, from which it can be inferred that the tremor is not under central control. In addition, tremor of the right and left hands does not show a synchronous relationship.

Chest conduction properties and ECG equalization.

In common practice of detecting and recording biomedical signals, it is often implicitly assumed that the propagation, through the whole circuit human body-electrodes recording devices, is frequency and voltage independent. As a consequence, clinicians are not aware that recorded signals do not correspond faithfully to the original electrical activity of organs under investigation. We have studied the transmission of electrical signals in human body at various voltages and frequencies to understand if and to which extent the most diffused stimulating and recording techniques used in medicine are affected by global body conduction properties. Our results show that, in order to obtain a more faithful detection of electrical activity produced or evoked by human organs (e.g. EGG, electromyography, etc.), it is convenient to 'equalize'' recorded signals. To this purpose, two equalization techniques are proposed, based, respectively, on a simple hardware filtering during acquisition, or FFT post-processing of the acquired signals. As an application, we have studied the transmission of electrical signal in human chest and have compared equalized high frequency ECG signals with raw (original) recordings.

[Erythrocyte deformability dependent on variations in pH]. / La deformabilita' degli eritrociti in rapporto a variazioni del pH.

Authors studied the influence of pH changes on red blood cell deformability by means of filtration technique. In 0,9% NaCl solutions, there was decrease of RBC deformability upon both lowering and increasing of pH. In Teitel solutions, RBC deformability increased on alcalyne pH.

[Erythrocyte deformability determined by filtration]. / Determinazione della deformabilita' degli eritrociti mediante filtrazione.

Authors studied red blood cell filtrability by means of an original apparatus. The red blood cells were suspended in 0,9% NaCl and Teitel solutions. Teitel solution was the most usefullness in filtrability studies.

The serum lipoprotein pattern of water buffalo (Bubalus bubalis).

1. The serum lipoprotein pattern of water buffalo was studied by means of electrophoresis and the lipoproteins were isolated by ultracentrifugation on the basis of their hydrated density. 2. High density lipoproteins (HDL) showed a higher level of cholesterol than did the other lipoproteins. Moreover, the level of phospholipids was higher in HDL than in very low density lipoproteins (VLDL). 3. The buffalo B100 apoprotein was similar to that of man and rat. Three apoproteins similar to human apo E, apo AI and AII were found in buffalo HDL, buffalo VLDL contained essentially apo B protein.